Housing containing a penetrable membrane sealing an evacuation outlet

ABSTRACT

The present invention relates to a diffusion and/or filtration apparatus, including a housing consisting of a cylindrical open-ended main part closed by two end caps and being provided with an inlet and outlet for a first fluid and at least one outlet for a second fluid having a penetrable membrane, said first fluid being adapted to flow through the fibers of a bundle of semipermeable hollow fibers arranged between two end walls within the housing and said second fluid being adapted to be removed from the space outside the fibers through said at least one outlet for the second fluid.

FIELD OF THE INVENTION

The present invention relates to diffusion and/or filtration apparatus.More particularly, the present invention relates to such apparatusincluding a housing with a cylindrical open-ended main portion closed bytwo end caps. Still more particularly, the present invention relates tosuch apparatus whereby a bundle of semipermeable hollow fibers, an inletand an outlet for a first fluid adapted to flow through the fibers, andan outlet for a fluid to be removed from the space outside of the hollowfibers between the ends of the housing which includes a penetrablemembrane. The present invention also relates to blanks for the mainportion of such housings and to methods of manufacturing such apparatus.

BACKGROUND OF THE INVENTION

Diffusion/filtration devices are used for different kinds of medicaltreatment, such as hemodialysis, hemofiltration, plasmapheresis andimmunotherapy. Other fields of use for such devices are for instancedialysis in general and filtration in general, for example in connectionwith cleaning or desalination of sea water.

In connection with the production of devices of the above kind, each endof a housing with a bundle of fibers placed therein is normally enclosedin a casting mold into which the material for the adjacent end wall isfed in a liquid condition, thereby penetrating into and around thefibers. This penetration is controlled by the casting in a manner suchthat the penetration into the fibers is less than that around thefibers, making it possible to open the ends of the fibers by making atransverse cut between the surfaces defined by the two differentpenetration depths.

The manner in which the end walls may be molded is described in moredetail, for example, in EP-B-0 165 478, and U.S. Pat. Nos. 4,227,295 and4,329,229, as well as in copending U.S. patent application Ser. No.237,504.

Before molding the end walls, the inside of the fibers, as well as theoutside of the fibers, are normally flushed by a cleaning liquid. Thisflushing is normally performed in a separate housing having the simpleform of an open-ended tube. If, instead, it should be performed in thefinal housing of the diffusion/filtration device, there is the risk thata portion of the cleaning liquid may remain in the housing, especiallyin inlets and outlets arranged in the housing wall.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a diffusion and/orfiltration apparatus in which the above-discussed flushing of the fibersbefore the molding of the end walls may be made in the final housing ofthe apparatus without the above-mentioned risks. According to thepresent invention, these and other objects have now been realized byusing a special blank for the main part of the diffusion and/orfiltration apparatus housing, with the completed housing consisting of acylindrical open-ended main portion closed by two end caps and beingprovided with an inlet and an outlet for a first fluid and a secondoutlet for a second fluid. The first fluid is adapted to flow throughthe fibers of a bundle of semipermeable hollow fibers arranged betweentwo end walls within the housing, and the second fluid is adapted to beremoved from the space outside the fibers through the second outlet.

The blank is characterized in that the second outlet, which is arrangedin the main part of the housing, is temporarily closed by a penetrablemembrane which prevents the flushing liquid from entering it.

Specifically, a diffusion/filtration apparatus in accordance with thepresent invention comprises a housing which defines a longitudinallyextending internal chamber including a first end and a second end. Abundle of semipermeable hollow fibers is disposed within the internalchamber, with the hollow fibers extending longitudinally from the firstend of the housing to the second end of the housing Thus, the hollowfibers also have a first end and a second end which correspond to thefirst end and the second end of the housing. Additionally, the hollowfibers have an outer surface.

First inlet means for the introduction of a fluid into the first end ofthe housing and first outlet means for the evacuation of a fluid fromthe second end of the housing are also provided. Additionally, secondoutlet means for the evacuation of a fluid from the internal chamber ofthe housing are provided at a location between the first and second endsof the housing. This second outlet includes a penetrable membrane.

The blank is preferably also provided with a second inlet for this otherfluid, which is also closed by a penetrable membrane. Such a secondinlet is necessary, if the apparatus is intended to be used fordialysis, for example. If on the other hand it is intended only to beused for filtration, a second inlet is not necessary, as a second outletfor the filtrate is all that is required for filtration.

When completed, the second outlets and inlets of the apparatus inaccordance with the present invention are at least partly opened in thatthe penetrable membrane, or membranes, have been penetrated.

This penetration can be made in such a way that a portion of thepenetrated membrane is disposed at an angle in relation to the openingcreated by the penetration. As a result, the membrane will serve as abaffle, guiding the flow of this second fluid.

The second outlet for the second fluid, and possible other outlets andinlets for this second fluid, consist preferably of a nipple arranged onthe wall of the housing, which is separated from the fiber bundle by afluid distribution channel. An advantage of this construction is thatthe membranes may be penetrated easily without damaging the fiberbundle.

The present invention also relates to a method of manufacturing adiffusion and/or filtration apparatus in accordance with the presentinvention.

The method is characterized in that the second outlet for the secondfluid, which is arranged on the main part of the housing is closed by atemporary closure before the inside and outside of the hollow fibers isflushed by the special flushing fluid. The fibers are arranged withinthe cylindrical open-ended main part of the housing, whereafter the endsof the fibers are molded into the end walls and opened by transverselycutting the entire apparatus. Whereupon, the apparatus is finallyprovided with two end caps.

Specifically, the method of the present invention comprises the stepsof; providing a bundle of semipermeable hollow fibers, these hollowfibers having a first end, a second end, outer surfaces and innersurfaces; providing a housing which defines a longitudinally extendinginternal chamber including a first end and a second end, and secondoutlet means for the evacuation of the internal chamber, the secondoutlet means being sealed from the internal chamber by a penetrablemembrane; inserting the bundle of hollow fibers into the internalchamber; flushing the inner and outer surfaces of the bundle of hollowfibers and the internal chamber of the housing with a flushing solution,inserting a predetermined quantity of a potting material to apredetermined penetration of the internal chamber, thus sealing theinternal chamber from the ends of the hollow fibers; cutting thehousing, the potting material and the hollow fibers transverse theinternal chamber at a predetermined point between the inlet and thepenetration of the potting material and attaching lid means over thefirst and second ends of the housing; and flushing the inside of thehollow fibers a second time in order to remove any possiblecontamination caused by the cutting.

Additionally, the penetrable membrane provides the possibility of makingthe above described baffles, which guide the flow of the second fluid.The penetrable membrane or any other temporary closure is preferablyarranged close to the inside wall of the cylindrical open-ended mainpart of the housing.

Preferably, after the opening of the ends of the hollow fibers thefibers are flushed a second time in order to remove any possiblecontamination due to the cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial, side elevational partially sectional view of anapparatus according to the present invention, at a first stage of itsmanufacture;

FIG. 2 is a partial, side, elevational, partially sectional view of theapparatus of FIG. 1 at a final stage of its manufacture;

FIG. 3a is a top, elevational, partially sectional view of the apparatusof FIG. 2, taken along Line I--I thereof; and

FIG. 3b is a top, elevational, partially sectional view of anotherembodiment of the apparatus shown in FIG. 2.

DETAILED DESCRIPTION

Referring next to the figures, in which like reference numerals refer tolike portions thereof, FIG. 1 shows a bundle of hollow fibers 1 in ahousing 2 before the molding of the end walls 3, as shown in FIG. 2. Anipple 4, intended to serve as the above mentioned second outlet, isarranged at an enlarged part 7 of the housing 2. At the end of thefibers 1, the bundle is supported by a restricted portion 5 of a ring 6.This ring 6 is intended to serve as an inlet and/or an outlet for aspecial flushing liquid intended for flushing the inside and the outsideof the fibers before the casting of the end wall 3. As described more indetail in copending U.S. patent application Ser. No. 237,504 filedsimultaneously with the present application, this ring 6 can also bemodified to serve as a part of the mold for the end wall 3.

The nipple 4 is, as mentioned above, arranged on an enlarged part 7 ofthe housing 2, which provides a distribution channel 8 for any liquidtaken into or out of the apparatus through the nipple 4.

In the blank shown in FIG. 1 the inner opening of the nipple 4 is closedby a penetrable membrane 9. As shown in FIG. 2 this membrane may be.partially penetrated in order to provide an opening 9a and an obliquelyarranged baffle 9b, also shown in FIG. 3a. The baffle may be formed by aheated die, and as a result of the form of the die it can either begiven the form 9b shown in FIG. 3a or the form 9c shown in FIG. 3b.Thus, providing different guidance for the fluid either entering orleaving through the nipple 4.

After the casting of the end walls 3 the ends of the fibers are openedby transversably cutting through the end walls and through the enlargedparts 7 of the housing 2. After a second flushing of the opened ends ofthe fibers, the apparatus is finally provided with a lid 10 with aninlet and/or outlet 11 for the fluid which is intended to be sentthrough the fibers.

As mentioned above, the invention also relates to a method ofmanufacturing a diffusion and/or filtration apparatus in accordance withthe present invention, i. e., including a housing 2 which consists of acylindrical open ended main portion closed by two end caps 10 and aninlet and an outlet 11 for a first fluid and a second outlet 4 for asecond fluid. The first fluid is thus adapted to flow through the bundleof semipermeable hollow fibers arranged between two end walls within thehousing, and the second fluid is adapted to be removed from the spaceoutside the fibers through the second outlet.

The method is characterized in that the second outlet 4 for the secondfluid, which is arranged in the main portion of the housing, is closedby a temporary closure before the inside and outside of the bundle ofhollow fibers is flushed by a special flushing fluid. Thereafter, theends of the fibers are molded into the end walls of the housing andopened by transversely cutting the entire apparatus. Whereupon, theapparatus is finally provided with the two end caps 10.

The temporary closure is preferably provided by a penetrable membrane 9arranged close to the inside wall of the cylindrical open-ended mainpart.

Additionally, in order to remove any possible contamination caused bythe cutting of the fibers, the now unitary structure is preferablyflushed a second time.

Specifically, the method of the present invention includes the steps of:providing a bundle of semi-permeable hollow fibers 1, the bundle ofhollow fibers 1 having a first end, a second end, outer surfaces, andinner surfaces;

Providing a housing 2 which defines a longitudinally extending internalchamber including a first end and a second end and second outlet means 4for the evacuation of the internal chamber, the second outlet meansbeing sealed from the internal chamber by a penetrable membrane 9, thepenetrable membrane 9 being arranged close to the inside wall of thehousing 2;

Inserting the bundle of hollow fibers 1 into the internal chamber, andflushing the inner and outer surfaces of the bundle of hollow fibers 1and the internal chamber of the housing with a flushing solution;

Inserting a predetermined quantity of a potting material to apredetermined penetration of the internal chamber, the potting materialsealing the internal chamber from the ends of the hollow fibers;

Cutting the housing, the potting material and the hollow fiberstransverse the longitudinal line defined by the internal chamber at apredetermined point between the inlet and the penetration of the pottingmaterial thus forming a sealed internal chamber;

Flushing the inside of the hollow fibers a second time in order toremove any possible contamination caused by the cutting; and

Attaching lid means 10 over the first and second ends of said housing.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

I claim:
 1. A diffusion/filtration structure comprising:(a) housingmeans, said housing means defining a longitudinally extending internalchamber including a first end and a second end; (b) a bundle ofsemi-permeable hollow fibers disposed within said internal chamber, saidhollow fibers extending longitudinally from said first end of saidhousing to said second end of said housing, said hollow fibers having anouter surface, and a first end and a second end corresponding to saidfirst end and said second end of said housing means; (c) first inletmeans for the introduction of a fluid into said first end of saidhousing means; (d) first outlet means for the evacuation of a fluid fromsaid second end of said housing means; and (e) second outlet means forthe evacuation of a fluid from said internal chamber disposed at alocation between said first and second ends of said housing means; (f)said second outlet means, including a penetrable membrane at an internallocation proximate said internal chamber sealing said second outletmeans from said internal chamber.
 2. The structure according to claim 1including second inlet means for the introduction of a fluid into saidinternal chamber disposed at a location between said first end and saidsecond end of said housing means, said second inlet means including apenetrable membrane sealing said second inlet from said internalchamber.
 3. The structure according to claim 1 wherein said penetrablemembrane include a penetrated portion defining an opening between saidsecond outlet means and said internal chamber.
 4. The structureaccording to claim 3 wherein said penetrated portion of said penetrablemembrane includes baffle means protruding into said internal chamber fordirecting the flow of said fluid within said internal chamber.
 5. Theapparatus according to claim 1 wherein said second outlet means includesa hollow nipple extending from said housing, said penetrable membranebeing disposed between said hollow nipple and said internal chamber. 6.The apparatus according to claim 5 wherein said penetrable membrane isdisposed proximate said internal chamber.
 7. The apparatus according toclaim 1 wherein said first end of said housing means includes anenlarged portion defining an annular space between said bundle ofsemi-permeable membranes and said housing means, and wherein said secondoutlet means is located in juxtaposition with said annular space,whereby said annular space can act as a distribution channel for saidfluid being evacuated from said internal chamber.